Heat a large skillet over high heat. Add 2 tablespoons of oil and after the oil is hot, carefully add the tofu into a single layer (hot oil may splatter). Sear each side for 2-3 minutes, or until golden and crisped. Remove the tofu from the pan and set aside.

Reduce the heat to medium and add the remaining tablespoon of oil. Stir in the shallots and garlic and then cook for about 1 minute, or until soft.

Stir in the peanut butter, hoisin, water, fish sauce, rice vinegar and brown sugar. Stir sauce until well combined and simmer on low heat for about 30 seconds, or until the sauce thickens and brown sugar is dissolved. If sauce is too thick, add more water as needed.

Serve tofu with the sauce either warm or at room temperature. Garnish with chopped peanuts when serving.